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Building and Housing Research Center

Iran Strong Motion Network

Catalogue of Earthquake Strong Ground Motion Records(2004)

Editor in Chief : Dr. Heidarinejad, Ghasem., President of BHRC

Associate Editor : Mirzaei Alavijeh, H., Executive Director of ISMN

Editorial Board : Mirzaei Alavijeh, H., Sinaeian, F., Farzanegan, E., Karimi, P., Safarzadeh, F.

and Mirsanjari, M.

Research Report

BHRC Publication No.: R-466

2007

Foreword Since 1973, Building and Housing Research Center (BHRC) with its advanced laboratories and equipments and people has the responsibility for performing various applied research projects on various as-pects of building and housing. Its research departments are as follows:• Architectural and Building Systems• Architectural of Housing and Building Systems• Building Installations• Building Materials and Products • Concrete Technology• Engineering Seismology• Environmental Design and Energy• Fire and Building• Geotechnical Engineering• Iran Strong Motion Network (ISMN)• Structural Engineering

The idea of establishing BHRC formed in 1970 within the framework of United Nations Development Program (UNDP). The major objectives for establishment of BHRC are:• Centralized provision and execution of research programs on building and housing by innovation of new methods and techniques,• Provision and publication of codes of practice and their application instructions,• Issuance of technical certificate for building products and systems,• Provision of technical guidance in construction and housing in compliance with national requirements, climatic and local considerations• Consideration needed for industrialized construction within the country. The Islamic Republic of Iran is amongst the most seismically active country. Destructive earthquakes shake the ground and whatever on it, targeting human lives and buildings. It dictated the needs for researches to prevent or at least to reduce the casualties. Therefore, in 1981, the duties of the earthquake engineering division of Management and Budget Planning Organization transferred to BHRC. The main responsibility of this newly established department in BHRC was managing, controlling and maintenance of National accel-erographic network. This network started with 270 analog instruments at the beginning, and recorded many valuable data of the occurred earthquakes. Because of the importance of to know more about the nature of this destructive phenomenon, at parallel, the other divisions of BHRC also started their researches in the relevant fields. The most important outcome of them was development of the Iranian Code of Practice for SeismicResistant Design of Buildings known as Standard 2800 published in 1987 for the first time. So far, BHRC hasissued two new editions of this Code of Practice and a large number of the other codes and regulations. This report deals with the records of the earthquakes occurred in 2004. We are highly determined to con-tinue presenting similar reports in the coming years. I hope it to be useful as a valuable source for those who are interested in this regard.

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Preface In order to reduce the earthquake hazard, a better understanding of seismic phenomenon and its im-pacts on the buildings and structures is necessary. This has led to increasing research activities in geophys-ics, engineering seismology and earthquake engineering along with development of the Iran Strong Motion Network (ISMN). Meanwhile, the occurrence of Manjil-Roudbar earthquake in June 20th, 1990, boosted the development of ISMN to 1200 digital accelerographs all over the country within a five years period. Mean-time, some of the old analog accelerographs are still at work. This network improvement enabled ISMN to record many weak to strong local earthquakes and provide a comprehensive and valuable strong motion database for the applied studies. The valuable records gathered via this network, were the main database used by many researches in the field of earthquake engineering and engineering seismology. Therefore, we in BHRC are keen for followingmore improvement and development of ISMN including:• The installation of new instruments in the seismically active area regarding the past recorded events,• Establishing the dense arrays for fault monitoring,• Establishing the down-hole arrays for site effect investigations,• Installation of accelerographs in most of the tall buildings for structure monitoring,• Installation of accelerographs in special structures including dams and other infrastructural structures to study their performance during an earthquake.These items were to be considered as the main goals in a successful improvement that was started since 2001. Beside the formal duties, the other activities including presentation of this network among the scien-tific and engineering communities in the Country were done. The other activities are as following:• Publishing and distributing the monthly newsletter of ISMN in Farsi as the only source of Strong Motion Data announcement• Producing a comprehensive accelerographic data bank• Establishing of ISMN webpage on BHRC web site for early information of recorded data for domes-tic and international use.At the time being, ISMN runs more than 1089 installed and ready to be triggered accelerographs through the Country. More than 6300 three-component accelerograms have been recorded, providing the most valuable database for researchers in the fields of engineering seismology, earthquake engineering, geology, seismotec-tonic and other related fields. Publishing the information of this databank in English could be a useful guidance for researchers, engineers and students. In this report as a comprehensive reference, the main recorded accelerograms in Iran along with the last revision of the strong motion parameters are introduced. As a turning point, we had started publishing a leaflet in English one for each year since 2001 and this is the fourth which is edition for2004. God willing, we are determined to continue Publishing next series of yearly issues in future. I hope it can be useful for researchers and communities interested in worldwide.

H.Mirzaei AlavijehISMN Executive Manager

VII

Contents

1. Iran Strong Motion Network 1

2. The Catalogue of Accelerograms recorded by ISMN in 2004 1

2.1. Izeh Earthquake (Khuzestan Province) 3 2.2 Bander-e-Assalooyeh Earthquake (Booshehr Province) 4 2.3 Minab Earthquake (Hormozgan Province) 5 2.4 Aftershock of Bam Earthquake (Kerman Province) 6 2.5 Aftershock of Bam Earthquake (Kerman province) 7 2.6 Golbaf Earthquake (Kerman province) 8 2.7 Mosha Earthquake (Tehran province) 9 2.8 Ahram Earthquake (Bushehr province) 10 2.9 Ali-Abad Earthquake (Golestan Province) 11 2.10 The Firouzabad-Kojour earthquake (Mazandaran province) 12 2.11 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran province) 18 2.12 Aftershock of Firouzabad-Kojaur Earthquake (Mazandaran province) 19 2.13 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran province) 20 2.14 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran province) 21 2.15 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran province) 22 2.16 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran province) 23 2.17 Boldaji Earthquake (Chaharmahal and Bakhtiyari Province) 24 2.18 Aftershock of Bam earthquake (Kerman province) 25 2.19 Robat Earthquake (Northern Khorasan Province) 26 2.20 Seyedtajedin Earthquake (Eastern Azerbaijan province) 27 2.21 Baneh Earthquake (Kurdistan Province) 28 2.22 Mohammadabad Earthquake (Kerman Province) 29 2.23 Agh Ghala earthquake (Golestan province) 30 2.24 Baravat Earthquake (Kerman province) 31 2.25 Aftershock of Agh Ghala earthquake (Golestan province) 32 2.26 Avaj Earthquake (Qazvin province) 33

Table of Recording Accelerograms During 2004 34

1. IRAN STRONG MOTION NETWORK

Iran Strong Motion Network (ISMN) started its activities in 1973 at the Planning and Budget Organization. In 1981, the Network transferred to Building and Housing Research Center and a new stage of its activities was born. The network has consisted of 274 accelerographs up to 1992, and grown up gradually, afterwards. In 2004, the network consisted of 1089 accelerographs stations (Figure 1) equipped with digital SSA-2 or analogue SMA-1 accelerographs. The trigger levels of all the instruments are set at 0.01g and more than 5650 accelerograms have recorded since January 1973 to December 2004. In 2004, due to 623 Accelerograms recorded of 319 earthquakes by 315 accelerograph stations and the maximum PGA of about 0.92g occurred in Hassankief station in Firouzabad-Kojour earthquake of May 28, 2004.

Figure 2: The number of accelerographs installed by BHRC

2. The Catalogue of Accelerograms recorded by ISMN in 2004 In this year, 623 accelerograms recorded by 315 accelerographs due to 319 earthquakes (Figure 2, 3) and the maximum PGA of about 0.92 g occurred in Hassankief station in Firouzabad -Kojour earthquake of May 28, 2004. The strong motion and seismological data of all accelerograms listed in table 1.The reports of the earthquakes with M≥5, or earthquakes with more than 3 recorded accelerograms are discused at the following.

Building and Housing Research CenterMinistry of Housing and Urban Development

Figure 3: Statistics of earthquakes happened in Iran in 2004

Figure 2: Location Map of accelerographs triggered in 2004

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2.1. Izeh Earthquake (Khuzestan Province) ISMN recorded a series of earthquakes that occurred in January 6, 2004, which struck South-West of Izeh city in the North of Khuzestan Province in South-West of Iran. Izeh, Bagh-Malek, Masjedsoleyman Dam and Masjedsoleyman Accelerograph stations recorded these earthquakes (Figure 4). The preliminary epicenter of the greatest earthquake (06:31:15 UTC) is located at 31.63N, 49.49E (IGTU) and 31.88N, 49.61E (NEIC). The peak ground acceleration were record at 37.45, 31.74 and 40.87 cm/s/s on L, V and T component in Izeh Station respectively.

Figure4: The location map of Izeh earthquake of January 6, 2004 and triggered stations

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2.2 Bander-e-Assalooyeh Earthquake (Booshehr Province) On January 14th 2004, at 16:58:58 (UTC), an earthquake with the magnitude of mb5.4 (NEIC), struck Asaluyeh area in Booshehr Province (South of Iran). Bandar-e-Asaluyeh station recorded this earthquake (Figure 5). The maximum peak ground acceleration was belonged to the Bandar-e-Asaluyeh station (30 cm/s/s). The epicenter of this earthquake has been located at 52.40E, 27.69N (NEIC).

Figure5: The location map of Bandar-e-Asalooyeh earthquake of January 14, 2004 and triggered stations

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2.3 Minab Earthquake (Hormozgan Province) On January 28th 2004, at 09:06:48 (UTC) an earthquake with the magnitude of Mb5.2 (NEIC), struck Minab area in Hormozgan Province (South of Iran). Minab and Goharan Accelerograph stations recorded this earthquake (Figure 6). The maximum peak ground acceleration was belonged to the Goharan station (16 cm/s/s). The epicenter of this earthquake has been located at 57.51E, 26.88N (NEIC)

Figure 6: The location map of Minab earthquake of January 28, 2004 and triggered stations

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2.4 Aftershock of Bam Earthquake (Kerman Province) On January 28th at 17:29:31(UTC) an earthquake with the magnitude of mb4.1 (NEIC), Mw3.5, Ml5.0 (BHRC) struck Bam area in Kerman Province. Bam, Baravat and Mich stations recorded this earthquake (Figure 7). The maximum peak ground acceleration was belonged to the Baravat station (24 cm/s/s). The epicenter of this earthquake has been located at 58.33E, 29.01N (NEIC) and 58.35E, 28.99N (BHRC).

Figure 7: The location map of Bam earthquake of January 6, 2004 and triggered stations

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2.5 Aftershock of Bam Earthquake (Kerman Province) An earthquake on February 11, 2004, at 04:02:43(UTC) with the magnitude of Ml4.9, Mw3.1 (BHRC) and mb3.6 (IGTU) occurred in Bam region. Bam, Baravat and Posht Rood accelerograph stations recorded this earthquake (Figure 8) and the maximum peak ground acceleration was belonged to the Poshtrood station (83 cm/s/s). The epicenter of this earthquake has been located at 58.25E, 28.79N (IGTU) and 58.38E, 29.18N (BHRC).

Figure 8: The location map of Bam earthquake of February 11, 2004 and triggered stations

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2.6 Golbaf Earthquake (Kerman province) An earthquake on February 13, 2004, at 14:02:16 (UTC) occurred in Golbaf region with the magnitude of Ml5.0, Mw3.5 (BHRC) and mb4.1 (IGTU).The epicenter of this earthquake has been located at 57.66E, 30.01N (BHRC) and 57.585E, 30.059N (IGTU). The accelerographs installed in Golbaf, Sirch and Joshan are recorded this earthquake (Figure 9). The maximum peak ground acceleration (25.91cm/s/s) is record in Joshan station.

Figure 9: The location map of Golbaf earthquake of February 13, 2004 and triggered stations

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2.7 Mosha Earthquake (Tehran province) IGTU reported an earthquake that occurred on February 21, 2004 at 12:07:04 (UTC) which struck North-East of Damavand city in the North of Iran. The accelerographs installed in Gazanak, Mosha and Damavand stations recorded this earthquake. The epicenter of the earthquake was located at 35.78N, 52.29E with the magnitude of mb 4.4 (Figure 10). The peak ground accelerations of 33.63, 30.2, 61.58 cm/s/s were record on L, V and T component respectively in Gazanak station.

Figure 10: location map of Mosha earthquake of February 21, 2004 and triggered stations

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2.8 Ahram Earthquake (Booshehr province) On March 02, 2004 at 07:51:45 (UTC), an earthquake having the magnitude of Mw5.4 (BHRC) and mb5.0 (IGTU) occurred in South in Booshehr Province. This earthquake is recorded by 12 sets of SSA-2 accelerographs. The maximum peak ground acceleration of about 0.41 g recorded in Abad station on T component (Figure 11). The epicenter of the earthquake has been located at 28.98N, 51.25E (IGTU), and 29.01N, 51.39E (BHRC).

Figure 11: The location map of Ahram earthquake of March 2, 2004 and triggered stations

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2.9 Ali-Abad Earthquake (Golestan Province) On March 27th at 01:31:23 (UTC) an earthquake with mb4.2 (NEIC), Mw4.7 and Ml5.4 (BHRC) occurred in Ramiyan in Golestan Province. The earthquake is recordeded by three sets of SSA-2 accelerographs of Golestan Province Strong Motion Network in Ali-Abad Ramyan and Ghaleno Kharagan stations (Figure 12). The maximum peak ground acceleration was belonged to Ali-Abad station (49 cm/s/s). The epicenter of this earthquake had been located at 36.87N, 55.06E (NEIC) and 36.74N and 54.89E (BHRC).

Figure 12: The location map of Ali-Abad earthquake of March 27, 2004 and triggered sta-

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2.10 The Firoozabad-Kojour earthquake (Mazandaran province) On friday afternoon of 28th May 2004, at 12:38:46 coordinated UTC (17:08:46 local time scale) a strong earthquake occurred between Baladeh and Marzan-Abad area (Mazandaran Province). The movements of this earthquake was felt in a vast area of the country and was led to public horror and anxiety. In spite of the fact that the shock was felt in the far surrounding, the dam-ages and life loss of this earthauake were fortunately limited, about which we can say the most important factor was the low intensity of population in the areas adjacent to the epicenter of the earthquake.The earthquake characteristics have been reported by various national and international institutes. The Institute of Geophisics of Tehran University (IGTU) reported the magnitude as mb5.5, and the US Geological Survey (USGS) reported the magnitude as Mw6.2 and the focal depth as 28.3 Km. Based on obtained accelerograms, the Building and Housing Research Center, has estimated the epicenter of the earthquake at 51.56E and 36.30N. The magnitude of the earthquake has been estimated as Ml6.1 by BHRC. The focal mechanism of some of the previous earthquakes of this area and also the rapid moment tensor solution of Firoozabad – Kojour Earthquake by USGS is illustrated in Figure 13.Based on this solution, the mechanism of the best double couple solution is of thrust type with strike slip component. USGS has estimated the seismic moment of the main shock about Mo=2.510 Nm which is equal to moment magnitude of Mw6.2. In the preliminary report of this earthquake (Figure 14), the focal depth is reported to be the range of 14 to 40 km based on the reports of vari-ous refrence. The studying of the recorded accelerograms represented the minimum ts-tp of 2.54 for the Poul station accelerograms which indicates a focal depth of less than 18Km.

Figure 13: Focal mechanism of the earthquakes of the area (USGS)

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Strong Ground Motion Data The Mainshock Data The mainshock of this earthquake is recorded by 148 accelerographs of Iran Strong Motion Network (ISMN). The closest station to the epicenter of the earthquake was Poul (Kojour) station, but the maximum acceleration recorded (uncorrected) by the Hassan keyf station with the peak values of 0.922g, 0.415g and 0.501g on L, V and T components respectively.

The Data of the Aftershocks The Poul accelerograph station has recorded 12 aftershocks. The first aftershock is recordedabout 2 minutes after the mainshock with the PGA of 0.012g. The largest aftershock (mb5.0) reported by IGTU, which occurred at 13:53:47 local time (9:23:47 UTC) on 29th May 2004. This aftershock has been also recorded by Poul accelerograph station with the PGA of 0.083g. The focal distance of this aftershock is estimated to be between 16-29Km from Poul (Kojour) station.

Figure 14: Focal mechanism of the earthquake

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Figure 15: The location Map of Firoozabad –K

ojour earthquake of My28, 2004 and triggered stations

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Figure 16: A residential building in Kelar Dasht

Figure 17: Taker village, 18 Km from the east of Baladeh

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Figure 18: Kelar Dasht municipality

Figure 19: Jahan Ara complex in Kelar Dasht, complete collapse of the pilot columns

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Figure 20: A residential building in Jahan Ara complex, Kelar Dasht

Figure 21: Abbas Abad road, Kelar Dasht: A building under construction

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2.11 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran Province) On 28th May at 19:47:02 (UTC) a moderate earthquake with the magnitude of mb4.5 (NEIC), ML5.2 and Mw4.3 (BHRC) occurred in Hasan Keyf area in Mazandaran Province. This earthquake happened about 7 hour after the mainshock of Firouz Abad-Kojur earthquake. Its epicenter estimated at 36.44N, 51.41E (NEIC). The strong motion due to this event was recorded by Poul, Karaj Dam2 and Hasan Keyf accelerographs (Figure 22), among them the maximum acceleration of about 42 cm/s/s occurred in Hasan Keyf station.

Figure 22: location map of Aftershock of Firoozabad-Kojour earthquake of May 28, 2004 and triggered stations

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2.12 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran Province) On May 29th 2004, at 09:23:47 (UTC) an earthquake with the magnitude of mb4.7 (NEIC) and Ml5.8 (BHRC), struck Poul area in Mazandaran Province. Noshahr, Noor, Hasan Keyf, Raiskola, Baladeh and Nahiyeh stations recorded this earthquake (Figure 23). The maximum peak ground acceleration was belonged to the Baladeh station (111 cm/s/s). The epicenter of this earthquake has been located at 51.37E, 36.40N (NEIC) and 51.29E, 36.37N (BHRC).


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2.13 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran Province) On May 29th at 11:01:30 (UTC) Poul city shaked again due to an earthquake with the magnitude of mb4.2 (NEIC), Ml5.0 (BHRC) struck Poul area in Mazandaran Province. Poul, Baladeh and Nahiyeh stations recorded this earthquake (Figure 24). The maximum peak ground acceleration of this event is recorded in Nahiyeh station (27 cm/s/s). The epicenter of this earthquake has been located at 51.39E, 36.47N (NEIC) and 51.27E, 36.36N (BHRC).


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2.14 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran Province) On May 29th of 2004 at 22:55:16 (UTC) an earthquake with Mw4.1, Ml5.1 (BHRC) occurred in Poul in Mazandaran Province. The earthquake is recorded by three sets of SSA-2 accelerographs of Poul, Baladeh and Nahiyeh stations (Figure 25). The maximum peak ground acceleration has occurred in the Baladeh station (16 cm/s/s). The epicenter of this event was located at 36.43N, 51.27E (BHRC).


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2.15 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran Province) On May 30th of 2004 at 01:42:38 (UTC), an earthquake with the magnitude of mb4.3 (NEIC) and Ml5.2 (BHRC) occurred in Mazandaran Province. The earthquake is recorded by four sets of SSA-2 accelerographs in Noshahr, Noor, Poul and Nahiyeh stations (Figure 26). The maximum peak ground acceleration was belonged to the Poul station (0.044 g). The epicenter of this earthquake has been located at 36.40N, 51.51E (NEIC) and 36.27N, 51.48E (BHRC).


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2.16 Aftershock of Firouzabad-Kojour Earthquake (Mazandaran Province) On May 30, 2004 at 19:26:59 UTC, an earthquake having the magnitude of Ml5.4, Mw4.6 (BHRC) occurred at North of Iran (Mazandaran Province). The earthquake is recorded by four sets of SSA-2 Accelerographs (Figure 27) by Iran strong motion network (BHRC). The maximum peak ground acceleration measuring about 0.057 g recorded in Poul station. The epicenter of this earthquake located at 36.41N, 51.38E (IGTU).


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2.17 Boldaji Earthquake (Chaharmahal and Bakhtiyari Province) On July 25th of 2004 at 14:45:43 (UTC) an earthquake with Mw4.2, Ml5.0 (BHRC) occurred in Boldaji in Chaharmahal and Bakhtiyari Province. The earthquake is recorded by three sets of SSA-2 accelerographs of Naqan, Boldaji and Shalamzar stations (Figure 28). The maximum peak ground acceleration has occurred in the Boldaji station (38 cm/s/s). The epicenter of this event was located at 32.13N, 50.91E (BHRC).

Figure 28: The location map of Boldaji earthquake of July25, 2004 and triggered stations

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2.18 Aftershock of Bam earthquake (Kerman province) On August 16th at 13:22:06(UTC) Bam city shaked again due to an earthquake with the magnitude of mb4.3 (NEIC), Ml5.2 (BHRC) struck Bam area in Kerman Province. Bam, PoshtRood and Khaje Asgar stations recorded this earthquake (Figure 29). The maximum peak ground acceleration of this event is recorded in PoshtRood station (105 cm/s/s). The epicenter of this earthquake has been located at 58.42E, 29.13N (NEIC) and 58.36E, 29.19N (BHRC).

Figure 29: The location map Aftershok of Bam earthquake of Aaugust 16, 2004 and triggered stations

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2.19 Robat Earthquake (Northern Khorasan Province) On August 21 2004 at 03:32:42 UTC, an earthquake with the magnitude of mb4.7 (NEIC) and Ml5.4 (BHRC) occurred in Northern Khorasan Province. Accelerograph stations of Robat, Garmakhan, Ashkhaneh, Raz and Bojnoord recorded this earthquake (Figure 30). This event caused the maximum peak ground acceleration of about 0.24 g that is recorded in the Robat station. The epicenter of this earthquake has been located at 57.62E, 37.76N (NEIC) and 57.47E, 37.89N (BHRC).

Figure 30: The location Map of August 21, 2004 Robat earthquake and triggered stations

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2.20 Seyedtajedin Earthquake (Eastern Azerbaijan province) On September 5th of 2004 at 17:33:58 (UTC), an earthquake with the magnitude of M3.9 (NEIC) and Ml5.1 (BHRC) occurred in Eastern Azarbaijan Province. The earthquake is recorded by five sets of SSA-2 accelerographs in Seyedtajedin, Sharafkhaneh, Marand, Zanjireh and Tasooj stations (Figure 31). The maximum peak ground acceleration was belonged to the Zanjireh station (0.027 g). The epicenter of this earthquake has been located at 38.56N, 45.32E (NEIC) and 38.37N, 45.20E (BHRC).

Figure 31: The location Map of September 5, 2004 Seyedtajedin earthquake and triggered stations

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2.21 Baneh Earthquake (Kurdistan Province) On October 5th of 2004, at 15:34:13 UTC, an earthquake having the magnitude of Mb4.6 (NEIC) and Ml5.0 (BHRC) occurred at west of Kurdistan Province. The earthquake recorded by three sets of SSA-2 Accelerographs, Armordeh, Kani Soor and Baneh by Iran strong motion network (Figure 32). The maximum peak ground acceleration (0.144 g) is recorded in Armordeh station. The epicenter of this earthquake has been located at 35.89N, 45.72E (NEIC) and 35.92N, 45.78E (BHRC).

Figure 32: The location Map of October5th, 2004 Baneh earthquake and triggered stations

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2.22 Mohammadabad Earthquake (Kerman Province) On October 6th of 2004, at 11:14:37 UTC, an earthquake having the magnitude of mb5.5 (IGTU), Mw5.1, Ml5.7 (BHRC) occurred in Jebalbarez region in Kerman Province. The earthquake is recorded by six sets of SSA-2 accelerographs in Mohammadabad, Darmazar, Jiroft Dam1, Jiroft Dam2, Qotb Abad and Abaragh stations by Iran strong motion network (Figure 33). The maximum peak ground acceleration was belonged to the Mohammadabad station the measuring about 0.12 g on L component. The epicenter of the earthquake has been located at 28.81N, 57.98E (BHRC), at 28.30N, 57.83E (IGTU) and at 28.76 N, 58.07 E (NEIC).

Figure 33: The location Map of Mohammadabad earthquake of October 6th, 2004 and triggered stations

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2.23 Agh Ghala earthquake (Golestan province) On October 7, 2004 at 21:46:18 UTC, an earthquake having the magnitude of mb5.9 (IGTU) occurred at North of Golestan province. The earthquake recorded by 32 sets of SSA-2 Accelerographs (Figure 34) by Iran strong motion network (BHRC). The maximum peak ground acceleration the measuring about 0.104 g is recorded in Gorgan station. The epicenter of this earthquake has been located at 37.215N, 54.459E (IGTU).

Figure 34: The location of Agh Ghala earthquake of October7, 2004and triggered stations

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2.24 Baravat Earthquake (Kerman province) On october 8th of 2004, at 07:16:01 (UTC) an earthquake with the magnitude of mb4.3 (IGTU) and Ml4.9 (BHRC) struck Bam area in Kerman Province. Bam1, Baravat, Abaragh, Khaje Asgar and Posht Rood1 stations recorded this earthquake (Figure 35). The maximum peak ground acceleration of about 48 cm/s/s is recorded in Baravat station. The epicenter of this earthquake has been located at 54.347E, 37.144N (IGTU) and 54.42E, 37.08N (BHRC).

Figure 35: The location Map of Baravat earthquake of October 8th, 2004 and triggered stations

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2.25 Aftershock of Agh Ghala earthquake One day after the mainshock of Agh Ghala earthquake on October 8th of 2004, at 13:45:55, an aftershock having the magnitude of mb4.8 (IGTU), Mw4.8 and Ml5.5 (BHRC) occurred at North of Golestan province. The earthquake is recorded by six sets of SSA-2 Accelerographs (Figure 36) in Agh Ghala, Bandar-e-Gaz, Inche Borun, Kowsar Dam, Voshmgir Sam and Gomishan stations. The maximum peak ground acceleration (0.037g) is recorded in Inche Borun station. The epicenter of this earthquake has been located at 29.101N, 58.402E (IGTU) and 29.18N, 58.42E (BHRC).

Figure 36: The location Map of Aftershock of Agh Ghala earthquake of October 8th, 2004 and triggered stations

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2.26 Avaj Earthquake (Qazvin province) On October 17, 2004 at 21:31:07 UTC, an earthquake having the magnitude of mb4.7 (IGTU), Mw4.3 and Ml5.2 (BHRC) occurred at Qazvin Province. The earthquake is recorded by Avaj, Changureh and Razan Accelerograph stations (Figure 37). The maximum peak ground acceleration of about 0.03 g is recorded in Changoureh station.The epicenter of this earthquake has located at 35.608N, 49.155E (IGTU) and 35.66N,48.96E (BHRC).

Figure 37: The location Map of Avaj earthquake of October 17th, 2004 and triggered stations

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Table1: Recorded Accelerograms during 2004

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